1. Recent Articles From Around The Web

    1. Optical Coherence Tomography Angiography Assessed Retinal and Choroidal Microvasculature Features in Patients with Retinitis Pigmentosa: A Meta-Analysis

      Optical Coherence Tomography Angiography Assessed Retinal and Choroidal Microvasculature Features in Patients with Retinitis Pigmentosa: A Meta-Analysis

      Background . The aim of this study was to assess the retinal and choroidal microvasculature features using optical coherence tomography angiography (OCTA) in patients with retinitis pigmentosa (RP). Methods . This study was a meta-analysis of relevant published studies that were included after a comprehensive search of PubMed, Embase, Cochrane Library, and Web of Science databases. Mean difference (MD) with a 95% confidence interval was used to assess continuous variable outcomes. Heterogeneity was evaluated using the chi-squared test based on the values of and I 2 . Results . Seven studies were included in this meta-analysis. The vessel density values measured in the superficial ...

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    2. The vascular densities of the macula and optic disc in normal eyes from children by optical coherence tomography angiography

      The vascular densities of the macula and optic disc in normal eyes from children by optical coherence tomography angiography

      Purpose This study aims to describe the variation and characteristics of vessel density (VD) of the macula and optic disc in the normal eyes of children. Methods This was a retrospective study where subjects aged 5–18 years with normal eyes were enrolled. The macula and optic disc were scanned by optical coherence tomography angiography (OCTA). The influences of age, gender, and axial length (AL) on VD were analyzed. Results A total of 71 normal eyes from 71 subjects were enrolled. For the macula, the mean VD of fovea, parafovea, and perifovea at superficial retina and deep retina were 20 ...

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    3. Three-dimensional choroidal vascularity index in acute central serous chorioretinopathy using swept-source optical coherence tomography

      Three-dimensional choroidal vascularity index in acute central serous chorioretinopathy using swept-source optical coherence tomography

      Purpose To evaluate the three-dimensional choroidal vascularity index (CVI) in the eyes with treatment-naïve acute central serous chorioretinopathy (CSC) using swept-source optical coherence tomography (SS OCT). Methods In this prospective cross-sectional study, OCT and OCT angiography covered an area of 12 × 12 mm centered on the fovea. Three-dimensional CVI was defined as the ratio of the choroidal vascular luminal volume to the total choroidal volume. The location of pigment epithelial detachment (PED) and the area with abnormal perfusion at choriocapillary layer were compared with the distribution of the three-dimensional CVI. Results Thirty-two eyes with treatment-naïve acute CSC, 18 ...

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    4. Optical coherence tomography angiography assessment of retinal microvascular changes in diabetic eyes in an urban safety-net hospital

      Optical coherence tomography angiography assessment of retinal microvascular changes in diabetic eyes in an urban safety-net hospital

      PURPOSE To determine whether quantitative optical coherence tomography angiography (OCTA) parameters can be used to distinguish among eyes at various stages of diabetic retinopathy (DR) in an urban safety-net hospital population. DESIGN Prospective cross-sectional study PARTICIPANTS 329 eyes from 329 patients were included in this study; 90 nondiabetic patients, 170 diabetic patients without retinopathy, 57 diabetes with mild to moderate NPDR, and 12 diabetes with severe NPDR to PDR. METHODS Patients underwent OCTA imaging and ultra-widefield fundus photography at Zuckerberg San Francisco General Hospital and Trauma Center between April and October 2018. For participants with diabetes, imaging was classified according ...

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      Mentions: UCSF
    5. Imaging Artifacts and Segmentation Errors With Wide-Field Swept-Source Optical Coherence Tomography Angiography in Diabetic Retinopathy

      Imaging Artifacts and Segmentation Errors With Wide-Field Swept-Source Optical Coherence Tomography Angiography in Diabetic Retinopathy

      Purpose : To analyze imaging artifacts and segmentation errors with wide-field swept-source optical coherence tomography angiography (SS-OCTA) in diabetic retinopathy (DR). Methods : We conducted a prospective, observational study at Massachusetts Eye and Ear from December 2018 to March 2019. Proliferative diabetic retinopathy (PDR), nonproliferative diabetic retinopathy (NPDR), diabetic patients with no diabetic retinopathy (DR), and healthy control eyes were included. All patients were imaged with a SS-OCTA and the Montage Angio (15 × 9 mm) was used for analysis. Images were independently evaluated by two graders using the motion artifact score (MAS). All statistical analyses were performed using SPSS 25.0 and ...

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    6. Correlation of optical attenuation coefficient estimated using optical coherence tomography with changes in astrocytes and neurons in a chronic photothrombosis stroke model

      Correlation of optical attenuation coefficient estimated using optical coherence tomography with changes in astrocytes and neurons in a chronic photothrombosis stroke model

      The optical attenuation coefficient (OAC) estimated using optical coherence tomography (OAC-OCT) offers a label-free 3D mapping of tissue infarction, but the physiological origin of the OAC contrast remains unclear. For effectively suppressing OAC fluctuations, we propose a hybrid (wavelength/angle) division multiplexing (HDM) method, which improved the OAC contrast by 70.7% in tissue phantoms. To test the feasibility of OAC-based infarction detection, triphenyltetrazolium chloride (TTC) staining was performed on fresh ex vivo brain slices, and the TTC-defined infarction was used as the ground truth. Sharp OAC contrast was observed between the TTC-defined infarction (1.09 mm −1 ) and normal ...

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    7. Full‐field swept‐source optical coherence tomography and neural tissue classification for deep brain imagingv

      Full‐field swept‐source optical coherence tomography and neural tissue classification for deep brain imagingv

      Optical coherence tomography can differentiate brain regions with intrinsic contrast and at a micron scale resolution. Such a device can be particularly useful as a realtime neurosurgical guidance tool. We present, to our knowledge, the first full‐field swept‐source optical coherence tomography system operating near a wavelength of 1310 nm. The proof‐of‐concept system was integrated with an endoscopic probe tip, that is compatible with deep brain stimulation keyhole neurosurgery. Neuroimaging experiments were performed on ex vivo brain tissues and in vivo in rat brains. Using classification algorithms involving texture features and optical attenuation, images were successfully classified ...

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    8. Etching-enabled extreme miniaturization of graded-index fiber-based optical coherence tomography probes

      Etching-enabled extreme miniaturization of graded-index fiber-based optical coherence tomography probes

      We introduced and validated a method to miniaturize graded-index (GRIN) fiber-based optical coherence tomography (OCT) probes down to 70  μm in diameter. The probes consist in an assembly of single-mode (SM), coreless (CL), and graded-index (GRIN) fibers. We opted for a probe design enabling controlled size reduction by hydrogen fluoride etching. The fabrication approach prevents nonuniform etching for both the GRIN and SM fiber components, while it requires no probe polishing postetching. We found that the miniaturized probes present insignificant loss of sensitivity (∼1  dB) compared to their thicker (125  μm) counterparts. We also showed that their focusing capabilities remain ...

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    9. Repeatability of Optical Coherence Tomography Angiography in Uveitic Eyes

      Repeatability of Optical Coherence Tomography Angiography in Uveitic Eyes

      Purpose : To investigate the intravisit repeatability of optical coherence tomography angiography (OCTA) in a cohort of uveitis patients. Methods : One hundred ten patients were imaged twice per eye, per visit, using the Zeiss Cirrus HD-OCT Model 5000 device. To calculate choriocapillaris flow void area (CC FV) 6 × 6-mm images were used, and 3 × 3-mm images were used to calculate vessel density (VD) and the foveal avascular zone area (FAZ) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP). Repeatability was measured using Bland-Altman analyses and intraclass correlation coefficients (ICC) with associated coefficient of variation (CV). Results : The level ...

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    10. Polarization sensitive optical coherence tomography using multiple polarization sensitive semiconductor optical amplifiers

      Polarization sensitive optical coherence tomography using multiple polarization sensitive semiconductor optical amplifiers

      This disclosure relates to an OCT apparatus configured to generate to electromagnetic (e.g., optical) signals having two different polarization states. Two or more silicon optical amplifiers (SOAs) can be configured to maintain a respective polarization state in an optical input signal provided from a light source (e.g., a broadband light source). The different polarization states can be combined by an optical combiner (e.g., a polarization maintaining fiber coupler) and provided to drive a reference arm and a sample arm implemented in an OCT system.

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    11. Apparatus and method for generating 3-D data for an anatomical target using optical fiber shape sensing

      Apparatus and method for generating 3-D data for an anatomical target using optical fiber shape sensing

      A fiber housing includes multiple shape sensing cores and a single optical core. A distal end of the fiber housing is positionable to direct the single optical core to a current point of an anatomical target. Collimated light over a first range of frequencies is projected from the single optical core to the current point. OFDR is used to detect reflected light scattered from the current point and to process the detected light to determine a distance to the current point. Light over a second range of frequencies is projected through the multiple shape sensing optical cores to the distal ...

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    12. Speckle reduction in optical coherence tomography images

      Speckle reduction in optical coherence tomography images

      An optical coherence tomography (OCT) image composed of a plurality of A-scans of a structure is analyzed by defining, for each A-scan, a set of neighboring A-scans surrounding the A-slices scan. Following an optional de-noising step, the neighboring A-scans are aligned in the imaging direction, then a matrix X is formed from the aligned A-scans, and matrix completion is performed to obtain a reduced speckle noise image.

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    13. Absolute linear-in-k spectrometer designs enabled by freeform optics

      Absolute linear-in-k spectrometer designs enabled by freeform optics

      Linear-in-wavenumber, k , spectrometers have the merits of saving signal processing time and improving the sensitivity of spectral-domain optical coherence tomography (SD-OCT) by avoiding post- k -interpolation. We report on an approach leveraging freeform optics to linearize spectrometers in k to achieve an extremely low residual k -nonlinearity in design. A freeform lens reduced the k -nonlinearity from 2.47% for a benchmark spectrometer to 2.79 × 10 −5 % and 3.36 × 10 −9 % using the Fringe Zernike coefficients up to the 16 th term and 37 th term, respectively. A simulation model was developed to evaluate the performance of SD-OCT ...

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    14. Association of retinal biomarkers and choroidal vascularity index on optical coherence tomography using binarization method in retinitis pigmentosa

      Association of retinal biomarkers and choroidal vascularity index on optical coherence tomography using binarization method in retinitis pigmentosa

      Purpose To investigate the association of retinal biomarkers with the choroidal parameters in retinitis pigmentosa (RP). Methods This prospective study included 69 eyes of 36 patients with RP. Choroidal vascularity index (CVI) was defined as the ratio of luminal area to stromal area after binarization on EDI–OCT images. Choroidal thickness (CT); peripapillary CT, the disruptions of the ellipsoid zone (EZ) and external limiting membrane (ELM); and the existence of disorganization of the retinal inner layers (DRIL) and epiretinal membrane (ERM) in central 1000 μm were noted. Results Having DRIL and the disruption of EZ and ELM was significantly associated ...

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    Optical Technology Stepping Forward ― Utility of Intracoronary Optical Coherence Tomography ― Human versus Machine: Comparing a Deep Learning Algorithm to Human Gradings for Detecting Glaucoma on Fundus Photographs Deep learning-based automated detection of retinal diseases using optical coherence tomography images Simultaneous morphological and flow imaging enabled by megahertz intravascular Doppler optical coherence tomography Robot prototype shows promise for microsurgery on eyes and aneurysms Optical coherence tomography through a rigid borescope applied to quantification of articular cartilage thickness in a porcine knee model Comparison of diagnostic performance in assessing the rewiring position into a jailed side branch between online 3D reconstruction systems version 1.1 and 1.2 derived from optical frequency domain imaging Thorlabs Extends MEMS-VCSEL Swept-Wavelength Laser Source Offering to Include 1060 nm Excess mucus viscosity and airway dehydration impact COPD airway clearance Optovue's 10-Part Video Series on Ophthalmic OCT Interpretation. Quantification of total haemoglobin concentrations in human whole blood by spectroscopic visible-light optical coherence tomography Does lining class-II cavities with flowable composite improve the interfacial adaptation?
  6. Recent Quotes

    1. “Our group has spent quite a few years working on developing the underlying imaging technology...This grant will support our translational efforts and allow us to identify ophthalmic surgeries that will directly benefit from real-time guidance and to better understand how surgical maneuvers impact postoperative visual function.
      By Yuankai K. Tao
    2. An historic issue with OCT is that the depth resolution is typically several times better than the lateral resolution...If the layers of imaged tissues happen to be horizontal, then they're well defined in the scan. But to extend the full power of OCT for live imaging of tissues throughout the body, a method for overcoming the tradeoff between lateral resolution and depth of imaging was needed.
      By Joseph A. Izatt
    3. With advances in microscopy techniques such as ours, we hope to change the way we detect, visualize and monitor diseases that will lead to better diagnosis, treatments and outcomes.
      By Stephen A. Boppart
    4. We’ve done a lot of benchtop imaging with micro-OCT, but this is the first time we’ve been able to use it in people...It’s unprecedented to see this pathophysiology dynamically in living patients. It will allow us to begin to understand things we never even knew were there.
      By Guillermo J. Tearney
    5. I’m so proud of the team here at NinePoint,...Our group over the years has really pushed the limits of engineering innovation to help patients. This past year has been especially fruitful, with the clearance and market launch of a first-of-its-kind artificial intelligence technology, and now with the clearance of a pancreatico-biliary application for the Low-Profile Optical Probe. The ability to promote to this new anatomical space really strengthens the platform of the NvisionVLE Imaging System, and continues to build the opportunity for this technology to help patients.
      By Eman Namati
    6. Imaging is more accurate, helps guide decisions and facilitates tailored therapy, especially in younger heart attack patients who more frequently have plaque erosion or non-atherosclerotic coronary artery disease.
      By Giulio Guagliumi
    7. We are very pleased with the outcomes of this study, which are the culmination of hard work by 47 physicians across 18 collaborating hospitals...What is further encouraging is that this study was undertaken without key technological improvements that have since been launched commercially. We anticipate that future studies using the Real-time Targeting laser marking feature and our newly launched artificial intelligence software, Intelligent Real-time Image Segmentation, will improve upon these already very positive results. Working together with our commercial partner, Merit Medical, and many of the leading hospitals in the United States, we are ecstatic that this technology continues to have an important and beneficial impact for patients.
      By Eman Namati
    8. We can’t use functional OCT/OCTA in the brain to look at neurovascular coupling at the cellular level because the brain is surrounded by the skull, and fine resolution isn’t possible...But we can use functional OCT/OCTA to examine the interactions between individual photoreceptors and their blood vessels in the retina, which is much more accessible in the eye.
      By Xincheng Yao
    9. With the NSTIN plot, the temporal quadrant of the retinal nerve fiber layer is displayed in the center of the B-scan. This portion of the disc is crucial for everyday visual function, and identification of abnormal thinning in this region is essential for managing glaucoma.
      By Donald C. Hood
    10. Conavi is delighted to receive approval for the clinical use of the Novasight Hybrid System in Canada and are thankful to the many researchers, clinicians, patients, employees and other stakeholders that made this milestone possible.
      By Brian K. Courtney